1. Field of the Invention
The present invention relates to a stereo image display technique, by which 2D or 3D image display may be switched in two display directions.
2. Description of Related Art
FIG. 1 is a cross-sectional view of a device provided by U.S. Pat. No. 7,255,671,903. As shown in FIG. 1, a backlight plate 100 provides a light source to a parallax barrier 101, wherein the parallax barrier 101 has transparent and opaque interlaced vertical strips for outputting light in interlaced strips, and in coordination with pixels within a transmissive display unit 102 and a position of human eyes. A first eye of an observer may observe a first image, and a second eye may observe a second image, such that a stereo display effect of 3D images separation for the left eye and the right eye is then achieved. As shown in FIG. 1, the left eye may only observe the pixels in odd columns 01, 03, 05, 07 and 09, and cannot observe the pixels in even columns; meanwhile, the right eye may only observe the pixels in the even columns 02, 04, 06, 08 and 10, and cannot observe the pixels in the odd columns, so as to form a stereo image in a vision system.
FIG. 2 is a diagram illustrating another conventional technique. A structural difference between the embodiments of FIG. 1 and FIG. 2 is that positions of the parallax barrier 101 and the transmissive display unit 102 are exchanged. In other words, in FIG. 1, the transmissive display unit 102 is disposed on the same side of the backlight plate 100 and the parallax barrier 101, while in FIG. 2, the transmissive display unit 102 is disposed between the backlight plate 100 and the parallax barrier 101. The effect achieved by the embodiment of FIG. 2 is the same to that of FIG. 1.
Another conventional technique is disclosed by U.S. Pat. No. 7,116,387. As shown in FIG. 3A and FIG. 3B, two pieces of microretarder plates 2 and 3 with vertical interlaced 0 wavelength and λ/2 wavelength retardation are provided, and based on relative horizontal movement of the two plates, two states of with parallax barrier and without parallax barrier may be switched, so as to switch between a 2D image display and a 3D image display. With coordination of the microretarder plate and a polarizing plate, switching between 2D and 3D image display then may be achieved based on movement of the microretarder plate. Moreover, a transmissive liquid crystal panel 1, two microretarder plates 2 and 3, a polarizing plate 4, a backlight module 5, two drivers 6 and 7 and a carrier 8 are illustrated in FIG. 3A and FIG. 3B.
A planar image output mode is illustrated in FIG. 3A, in which when retardation patterns of the two microretarder plates 2 and 3 are overlapped, polarized light may substantially pass through, and the display unit 1 then displays a planar image. Moreover, a stereo image output mode is illustrated in FIG. 3B, in which when allocation of the retardation patterns of the two microretarder plates 2 and 3 are interlaced, striped intervals with 0 and λ/2 wavelength retardation are generated, such that the light is output in interlaced strips. Therefore, the display unit 1 then displays a stereo image, and accordingly 2D and 3D display modes may be switched.
However, the conventional display structures may only have the 3D display effect in one display direction, for example the horizontal direction, and therefore application thereof is limited.